Commit 88d57da163 incorrectly merged, because the syntax of `mref` has
changed to support unboxed floating-point arithmetic.
original commit: a8eeb536aecc0e0a363aa68d43edafa7d6c9df52
In CS, if you interrupt an especially tight non-tail recursion, such
as
(let loop ()
(cons 1 (loop)))
then the "context" view of the continuation (as recorded in a
continuation mark set) can take space that is a multiple of the size
of the continuation itself. That's a particular problem if the
too-deep recursion triggers the memory limit in DrRacket, because
DrRacket will then need a multiple of its current heap space to report
"out of memory".
(Note: Just keeping the continuation itself is not a good option,
because that may retain other data referenced by the continuation.)
This commit reduces the heap space used to gather a continuation
context, relying in part on new Chez Scheme support, but mostly it
limits the context length to roughly the same maximum as in BC. The BC
limit is an implementation artifact, but it turns out to have good
properties; informaiton on more than 64k continuation frames is rarely
useful. The limit could be a parameter, but a large built-in limit
seems likely good enough.
(Another note: Adding a limit argument to
`continuation-mark-set->context` doesn't help enough, because it's too
late by that point; too much memory has been used to repersent the
information that's in the mark set.)
The commit also tightens tracking of continuations for memory
accounting, reducing the chance that a thread's large continuation
will be charged to the wrong custodian.
samth said "I don't think the Friendly Environment policy should be thought of as part of copyright issues, or applying only to people who contribute code. Is there a different phrasing that would accomplish what you want here?" I have rephrased the reference to the Friendly Environment Policy and moved it before the License section to avoid confusion with copyright issues.
- A part of contract-out's code generation for struct assumes that
there's no parent struct and uses the provided struct name for
everything. This causes duplicate definitions when there are duplicate
field names where one is in a child struct and another is
in a parent struct. This PR fixes the problem.
- Disallow multiple #:omit-constructor
- Deprecate super-id. This information is unnecessary since we can
extract it from static struct information already. Attempting to
check that super-id is well-formed is error-prone due to how
the super struct type could be contracted which shields us from
detecting that they are indeed the super type.
- Utilize static struct field name information, and provide
the information when exporting a struct.
This PR is largely based on #732.
Fixes: #3266, #3269, #3271, and #3272
Especially fix problems with `__collect_safe`, but also deallocate
stack space for `&` returns.
original commit: b593b0f14e7a803d8e089f49e266194245504197
This commit adds `prop:struct-field-info` which is implemented to provide
static information about field names. The property is attached to all
struct types generated by `define-struct`.
The commit also modifies kernstructs to have the property.
Finally, the commit switches `struct-copy` to use the static field name
information when it's available.
It remains to change `contract-out` and `match`'s `struct*` to
recognize/attach this new property, but this could be done
separately in the future.
This PR is largely based on racket/racket#732, though the approach is slightly
different.
